Home / G. Health and nutrition / Part IND

G18

"Fruitarianism isn't healthy, so veganism isn't either"

Before answering: an indirect argument

This argument is about health and nutrition, not whether animals deserve respect. Many activists question this kind of argument in defending animals, because it sidesteps what matters: no one defends the rights of people who face discrimination by saying that treating them fairly is good for the environment.

Why it is not good to use it, or why always to pair it with an ethical argument: If veganism were defended on health grounds, anyone who manages to be healthy eating animals, and many people do, would have no reason to change. And if an animal product turned out to be demonstrably healthier, the same argument would start defending exploitation. The eater's health says nothing about whether what is done to the animal is just.

When used to justify exploitation, arguments like this one usually fail twice. They get the facts wrong, which often arrive distorted. And they get the morality wrong, because they leap from what is to what ought to be: even a real benefit would not show it is just to make someone suffer and die to obtain it.

So show the facts and correct what is wrong, but always come back to what matters: respect for animals and justice toward them. Learn why

The answer in one sentence

veganism isn't fruitarianism. An all-fruit diet is genuinely restrictive and risky, especially for children, and it's honest to say so. But a vegan diet includes beans, lentils, grains, nuts, seeds, vegetables, fortified foods and a vitamin B12 supplement, and nutrition bodies consider it, when well planned, adequate at every stage of life. Criticizing the most extreme diet in the group says nothing about the others.

Short answer

I agree that eating only fruit isn't healthy, especially for children. But that isn't veganism. A vegan diet has beans, lentils, chickpeas, rice, nuts, vegetables and a B12 supplement, and nutrition bodies consider it, when well planned, adequate at every stage of life. It would be like saying eating meat is harmful because a strict carnivore diet is risky.

For children

Imagine someone who eats only bread, nothing else. Their body would be missing a lot, wouldn't it? That doesn't mean bread is bad, or that people who eat bread are wrong. It means eating just one thing isn't enough. It's the same with vegans: eating only fruit isn't good, but vegans eat beans, rice, vegetables, nuts and lots more.

Ask a question back

"If someone ate only meat and got sick, would you conclude that every diet with meat is dangerous?"

Como pode aparecer

"People who only eat fruit get sick."

Everyday conversation

"Veganism is fruit and salad; that doesn't sustain anyone."

Everyday conversation

"I saw a video of a skeletal fruitarian. That's what veganism does."

Social media

"Do you really think you can live on bananas?"

Rhetorical question

"Restrictive plant-based diets increase the risk of malnutrition."

Academic version

"I know someone who got sick being vegan." (which is G10)

Disguised version

The strongest version

How it is said

"Those people who only eat fruit get sick. That's veganism; it isn't healthy."

Strongest version (steelman):

P1All-fruit diets cause deficiencies in protein, vitamin B12, calcium, iron, zinc and other nutrients.
P2Fruitarianism is a form of plant-based eating, advocated by some vegans.
P3If one form of plant-based eating is dangerous, the others probably are too.
CSo veganism isn't healthy.

P1 is true, and vegans shouldn't deny it. P2 is true only for a minority. The problem lies in P3, which generalizes from the most restrictive diet to all of them.

The argument is invalid: from the flaws of one specific diet, the flaws of every diet without animal products don't follow.

Full answer

Reconstruction and diagnosis

The argument takes the part for the whole:

Diet	What it includes	Assessment
Fruitarianism	Mostly fruit, sometimes nuts and seeds	Restrictive; risk of deficiencies, especially in children
A planned vegan diet	Legumes, grains, nuts, seeds, vegetables, fruit, fortified foods, B12 supplement	Considered adequate at every stage of life by nutrition bodies
Veganism (as an ethical position)	Not exploiting animals, as far as possible and practicable	Not a specific diet

b
Where the argument breaks
1. Veganism isn't a specific diet.
It's an ethical position against the exploitation of animals. There are many ways to eat without animal products, and most vegans aren't fruitarians.
2. The criticism of fruitarianism is valid, and doesn't reach the rest.
All-fruit diets can cause deficiencies in protein, B12, calcium, iron, zinc and other nutrients, and they're unsuitable for children. That says something about that diet, not about eating beans and rice.
3. The position of nutrition bodies.
The Academy of Nutrition and Dietetics, the largest association of nutrition professionals in the United States, states that appropriately planned vegetarian diets, including vegan diets, are healthful and nutritionally adequate at every stage of life. The crucial point is planning, including B12 (G3).
4. The same logic would apply to meat eaters.
A strict carnivore diet, meat only, is also restrictive and has risks. No one would conclude from it that every diet with meat is dangerous (G12).
5. Vegans shouldn't romanticize fruitarianism either.
Saying "humans are frugivores by nature" is a weak argument this guide asks people to stop using (V30). Defending animals doesn't require defending extreme diets.

Data and sources

Source	What it says	Note
Melina, Craig and Levin, 2016	Appropriately planned vegetarian, including vegan, diets are healthful, nutritionally adequate and appropriate for all stages of life	Position of the Academy of Nutrition and Dietetics
NIH, Office of Dietary Supplements, vitamin B12	Natural sources of B12 are limited to animal foods; vegans need fortified foods or supplements
Wikipedia, "Fruitarianism"	Gathers sources on the risks of fruitarianism: deficiencies in protein, B12, calcium, iron, zinc and fatty acids, and unsuitability for children	Used as an overview, with the sources cited in the article

d
The strongest counter-reply: plant-based diets demand too much care
The most serious version says: even if veganism isn't fruitarianism, any diet without animal products requires planning and supplementation, and many people don't do it right. In practice there would be more risk than with the usual diet.
e
Why the counter-reply doesn't reach the conclusion
Every diet requires some care.
Usual diets also have common problems, such as too much salt and ultra-processed food and too little fiber.
Supplementing is normal.
Iodized salt, fortified flour and the supplementation of farm animals themselves show that fortifying and supplementing are part of many diets.
Difficulty isn't impossibility.
That some people plan poorly doesn't show the diet is inadequate for those who plan well.
f
Back to the moral question
Even if a vegan diet required more attention, the question would remain the same: does the effort of planning one's meals justify breeding and killing animals that feel? Health can correct facts about diet, but it doesn't decide whether it's just to exploit someone.

Reasoning errors

Logical

Is the form valid?

Composition, part for the whole

Takes the most restrictive diet as if it were all of veganism

Straw man

Attacks fruitarianism and concludes against veganism

Epistemological

Does the evidence support it?

Generalizing from extreme cases

Uses cases of malnutrition as the rule

Moral

Is the criterion coherent?

Health as a moral justification

Uses a nutritional risk to dismiss the question of harm to animals

Biases

Availability heuristic

Extreme, shocking cases stick in memory

General literature on availability

Rationalization through the 4Ns

"Necessary" justifies continuing to eat animals

Piazza et al., 2015

Confirmation bias

Seeks the worst examples to confirm one's opinion

General literature on confirmation bias

Extrapolations

The principle being tested is: "if the most extreme version of a diet is harmful, every version is".

If it applied to…Diets with meatTap to see

The strict carnivore diet would condemn every diet with meat

No one accepts this

If it applied to…FastingTap to see

The risks of prolonged fasting would condemn skipping a meal

Absurd

If it applied to…SportTap to see

The risks of ultramarathons would condemn walking

Absurd

Contradictions

Doesn't judge every diet with meat by the strict carnivore diet.

But judges all of veganism by fruitarianism.

Accepts supplements and fortified foods.

Such as iodized salt and enriched flour.

Eats fruit, beans and rice.

Vegan foods that are part of their own diet.

What the argument gets right

What is true

It's right that fruitarianism is a risky diet, which can cause serious deficiencies and is unsuitable for children. Vegans shouldn't promote it as a model or use the idea that humans are "frugivores by nature".

But

But veganism isn't fruitarianism. A varied, well-planned vegan diet with B12 is considered adequate by nutrition bodies. And even if it required more care, that wouldn't answer the question of what we do to animals.

Connections

Usually comes before

G16 Vegans are weak, pale and depressed.The stereotype rests on the image of the extreme diet

G18this argument

Usually comes after

G1 We need animal protein.From the all-fruit diet it moves to protein

G3 If you need B12 supplements, it isn't natural.Supplementation becomes the objection

G10 I know someone who got sick being vegan.One case becomes the rule

G12 A carnivore, paleo or keto diet is healthiest.The extreme diet on the other side appears as the solution

G19 Veganism is an eating disorder in disguiseThe restrictive diet becomes the model for all of veganism

References

Nutrition

Psychology

Rationalizing meat consumption. The 4Ns. *Appetite*, 91.